CD4 and Patent ductus arteriosus: Compared with that in M/PDA, the IHC score of tumour-infiltrating CD4-Treg cells (expressing FOXP3) in GSRC was higher, and the difference was statistically significant (Wilcoxon rank-sum test, p = 0.0032); The IHC score of tumour-infiltrating CD8-Teff cells (expressing KLRD1) was lower in GSRC, and the difference was statistically significant (Wilcoxon rank-sum test, p = 0.0021) (Fig. 6f, Supplementary Fig. 5).